AC light emitting diode and AC LED drive methods and apparatus

ABSTRACT

An AC LED package and circuits are disclosed along with an AC LED driver. The AC LED circuit may include as few as one LED or an array of anti-parallel LEDs driven with AC power sources and AC LED drivers at various voltages and frequencies. The AC LEDs are pre-packaged in various forms and materials and designed for mains or high frequency coupling in various forms to AC power sources, inverter type drivers or packages. The AC LED driver is a fixed frequency driver that provides a relatively constant voltage output to different size loads within the wattage limitation of the driver and in some cases is a direct mains power source.

RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 60/547,653, filed Feb. 25, 2005 and U.S. Provisional Application No.60/559,867, filed Apr. 6, 2004, both of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention generally relates to light emitting diodes(“LEDs”) and LED drivers. The present invention specifically relates toalternating current (“AC”) driven LEDs, LED circuits and AC drivecircuits and methods.

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to light emitting diodes(“LEDs”) and LED drivers. The present invention specifically relates toalternating current (“AC”) driven LEDs, LED circuits and AC drivecircuits and methods.

2. Description of the Related Art

LEDs are semiconductor devices that produce light when a current issupplied to them. LEDs are intrinsically DC devices that only passcurrent in one polarity and historically have been driven by DC voltagesources using resistors, current regulators and voltage regulators tolimit the voltage and current delivered to the LED. Some LEDs haveresistors built into the LED package providing a higher voltage LEDtypically driven with 5V DC or 12V DC.

With proper design considerations LEDs may be driven more efficientlywith AC than with DC drive schemes. LED based lighting may be used forgeneral lighting, specialty lighting, signs and decoration such as forChristmas tree lighting. For example, U.S. Pat. No. 5,495,147 entitledLED LIGHT STRING SYSTEM to Lanzisera (hereinafter “Lanzisera”) and U.S.Pat. No. 4,984,999 entitled STRING OF LIGHTS SPECIFICATION to Leake(hereinafter “Leake”) describes different forms of LED based lightstrings. In both Lanzisera and Leake, exemplary light strings aredescribed employing purely parallel wiring of discrete LED lamps using astep-down transformer and rectifier power conversion scheme. This typeof LED light string converts input electrical power, usually assumed tobe the common U.S. household power of 110 VAC, to a low voltage,rectified to nearly DC input.

Pat. Pending Application No. 0015968A1 entitled PREFERRED EMBODIMENT TOLED LIGHT STRING to Allen (hereinafter “Allen”) discloses AC poweredLED-based light strings. Allen describes LED light strings employingseries parallel blocks with a voltage matching requirement for direct ACdrive placing fundamental restrictions on the number of diodes (LEDs) oneach diode series block, depending on the types of diodes used. Allendiscloses that for the forward voltage to be “matched,” in each seriesblock, the peak input voltage must be less than or equal to the sum ofthe maximum forward voltages for each series block in order to preventover-driving.

LEDs can be operated from an AC source more efficiently if they areconnected in an “opposing parallel” configuration as shown by WO98/02020and JP11/330561. More efficient LED lighting systems can be designedusing high frequency AC drivers as shown by Patent Publication Number20030122502 entitled Light Emitting Diode Driver (“Clauberg et. al.”)Clauberg et. al. discloses that higher frequency inverters may be usedto drive an opposing parallel LED pair, an opposing parallel LED stringand/or an opposing parallel LED matrix by coupling the LEDs to a highfrequency inverter through a resonant impedance circuit that includes afirst capacitor coupled in series to one or more inductors with theimpedance circuit coupled in series to opposing parallel LEDs with eachset of LEDs having a second series capacitor in series to the impedancecircuit. In this system additional opposing parallel configurations ofLEDs with capacitors may not be added to or removed from the output ofthe driver without effecting the lumens output of the previouslyconnected LED circuits unless the driver or components at the driverand/or the opposing parallel LED capacitors were replaced with propervalues. By adding or removing the opposing parallel LED circuits thevoltage would increase or drop at the inductor and the current wouldincrease or drop through the first series capacitor as the load changedtherefore the inductor and all capacitors or entire driver would need tobe replaced or adjusted each time additional LEDs were added to orremoved from the system.

Patent application number US2004/0080941 entitled Light Emitting DiodesFor High AC Voltage Operation And General Lighting discloses that aplurality of opposing parallel series strings of LEDs can be integratedinto a single chip and driven with high voltage low frequency mains ACpower sources as long as there are enough LEDs in each opposing parallelseries string of LEDs to drop the total source voltage across the seriesLEDs within the chip. Patent numbers WO2004023568 and JP2004006582disclose that a plurality of opposing parallel series strings oropposing parallel series matrix of LEDs can be integrated into a singlechip and mounted on an insulating substrate and driven with a high drivevoltage and low drive current as long as there are enough LEDs in eachopposing parallel series string of LEDs to drop the total source voltageacross the series LEDs within the chip. These patents and applicationdisclose that for single chip or packaged LED circuits a plurality ofopposing parallel series strings are required with the total number ofLEDs in each series string needing to be equal to or greater than the ACvoltage source in order to drop the total forward voltage and providethe required drive current when driven direct with low frequency ACmains power sources.

The present invention addresses the above-noted shortcomings of theprior art while providing additional benefits and advantages

SUMMARY OF THE INVENTION

According to one broad aspect of the invention a lighting system isprovided having two or more LED circuits. Each LED circuit has at leasttwo diodes connected to each other in opposing parallel relation, atleast one of which such diodes is an LED. At least one capacitor isconnected to and is part of each opposing parallel LED circuit. Thecapacitor has only one end connected to the opposing parallel LEDs. Adriver is connected to the one or more LED circuits, the driverproviding AC voltage and current to the one or more LED circuits. Thedriver and the LED circuits form a driven circuit. The driver and theLED circuits are also configured such that LED circuits may be added toor subtracted (intentionally or by component failure) from the drivencircuit:

(a) without significantly affecting the pre-determined desired outputrange of light from any individual LED; and,

(b) without the need to: (i) change the value of any discrete component;or, (ii) to add or subtract any discrete components, of any of thepre-existing driven circuit components which remain after the change. Inanother embodiment of the invention at least one resistor is connectedto and is part of each opposing parallel LED circuit noted above. Theresistor is connected in series with the at least one capacitor.

According to another aspect of the invention LED circuit (sometimesreferred to as an “AC LED”) can comprise two opposing parallel LEDs, anopposing parallel LED string or an opposing parallel LED matrix having acapacitor in series to at least one junction of the connected opposingparallel configurations within a single chip, a single package, anassembly or a module.

When a real capacitor is connected in series in one or more linesbetween an LED and an AC power source, there is a displacement currentthrough that capacity of magnitude: I=2ΠfCV. The capacitor in the LEDcircuits of the invention regulates the amount of current and forwardvoltage delivered to the one or more opposing parallel LEDs based on thevoltage and frequency provided by the AC driver. Based on the number ofLEDs in the LED circuit the opposing parallel connections provide two ormore junctions for at least one series capacitor to be connected inseries of at least one power connection lead. In some embodiments, LEDcircuits use a series resistor in addition to the capacitor providing an“RC” resistor capacitor network for certain LED circuit driver couplingthat does not provide protection against surge currents to the LEDcircuits.

It should be noted that “package” or “packaged” is defined herein as anintegrated unit meant to be used as a discrete component in either ofthe manufacture, assembly, installation, or modification of an LEDlighting device or system. Such a package includes LED's of desiredcharacteristics with capacitors and or resistors sized relative to thespecifications of the chosen opposing parallel LED's to which they willbe connected in series and with respect to a predetermined AC voltageand frequency.

Preferred embodiments of a package may include an insulating substratewhereon the LEDs, capacitors and or resistors are formed or mounted. Insuch preferred embodiments of a package the substrate will includeelectrodes or leads for uniform connection of the package to a device orsystem associated with an AC driver or power source. The electrodes,leads, and uniform connection may include any currently known meansincluding mechanical fit, and/or soldering. The substrate may be such assapphire, silicon carbide, galium nitride, ceramics, printed circuitboard material, or other materials for hosting circuit components.

A package in certain applications may preferably also include a heatsink, a reflective material, a lens for directing light, phosphor,nano-crystals or other light changing or enhancing substances. In sum,according to one aspect of the invention, the LED circuits and ACdrivers of the present invention permit pre-packaging of the LED portionof a lighting system to be used with standardized drivers of knownspecified voltage and frequency output. Such packages can be of variedmake up and can be combined with each other to create desired systemsgiven the scalable and compatible arrangements possible with, andresulting from, the invention.

According to one aspect of the invention, AC driven LED circuits (or“driven circuits”) permit or enable lighting systems where LED circuitsmay be added to or subtracted (either by choice or by way of a failureof a diode) from the driven circuit without significantly affecting thepre-determined desired output range of light from any individual LEDand, without the need to: (i) change the value of any discretecomponent; or, (ii) to add or subtract any discrete components, of anyof the pre-existing driven circuit components which remain after thechange. During design of a lighting system, one attribute of the LEDschosen will be the amount of light provided during operation. In thiscontext, it should be understood that depending on the operatingparameters of the driver chosen, the stability or range of the voltageand frequency of the driver will vary from the nominal specificationbased upon various factors including but not limited to, the addition orsubtraction of the LED circuits to which it becomes connected ordisconnected. Accordingly, as sometimes referred to herein, driversaccording to the invention are described as providing “relativelyconstant” or “fixed” voltage and frequency. The extent of this relativerange may be considered in light of the acceptable range of light outputdesired from the resulting circuit at the before, during, or after achange has been made to the lighting system as a whole. Thus it will beexpected that a pre-determined range of desired light output will bedetermined within which the driven LED circuits of the invention willperform whether or not additional or different LED circuits have beenadded or taken out of the driven circuit as a whole.

According to another aspect of the invention and LED circuit may be atleast one pre-packaged LED and one pre-packaged diode connected togetheropposing parallel of each other, two opposing parallel pre-packagedLEDs, an opposing parallel LED string of pre-packaged LEDs or anopposing parallel LED matrix of pre-packaged LEDs having a capacitor inseries of at least one junction of the connected LED circuits. The LEDcircuit capacitor allows for direct coupling of at least one LED circuitto the LED driver without additional series components such ascapacitors and/or inductors between the LED circuit driver and the LEDcircuits. The LED circuit driver provides a relatively fixed voltage andrelatively fixed frequency AC output even with changes to the load usingfeedback AC voltage regulator circuitry. The LED circuit's may bedirectly coupled and scaled in quantity to the LED circuit driverwithout affecting the other LED circuit's lumen output as long as theLED circuit driver maintains a relatively fixed voltage and relativelyfixed frequency AC output.

According to an aspect of the invention, an LED circuit driver providesa relatively fixed voltage and relatively fixed frequency AC output suchas mains power sources. The LED circuit driver output voltage andfrequency delivered to the LED circuit may be higher or lower than mainspower voltage and frequencies by using an LED circuit inverter driver.The LED circuit inverter driver providing higher frequencies is requiredfor LED circuits that are integrated into small form LED packages thatinclude integrated capacitors or resistor capacitor “RC” networks. TheLED circuit inverter driver has feedback circuitry such as a resistordivider network or other means allowing it to sense changes to the loadand re-adjust the frequency and/or voltage output of the LED circuitdriver to a desired relatively fixed value. The LED circuit driver mayalso provide a soft-start feature that reduces or eliminates any surgecurrent from being delivered to the LED circuit when the LED circuitdriver is turned on. Higher frequency and lower voltage LED circuitinverter drivers are preferred enabling smaller package designs of LEDcircuits as the capacitor at higher frequencies would be reduced in sizemaking it easier to integrate into a single LED circuit chip, package,assembly or module.

According to the invention LED circuits may have a resistor capacitor(“RC”) network connected together in series or separate to the connectedjunction or junctions of the LED circuits. The maximum resistor valueneeded is only that value of resistance needed to protect the one ormore LEDs within the LED circuit from surge currents that may bedelivered by LED circuit drivers that do not provide soft start or otheranti surge current features. Direct mains power coupling would requireRC network type LED circuits as the mains power source delivers surgecurrents when directly coupled to an LED circuit.

The higher frequency LED circuit inverter driver may be a halogen orhigh intensity discharge (HID) lamp type driver with designmodifications for providing a relatively fixed voltage and relativelyfixed frequency output as the LED circuit load changes. Meaning if theLED circuit inverter driver is designed to have an output voltage of 12Vat a frequency of 50 Khz the LED circuit driver would provide thisoutput as a relatively constant output to a load having one or more thanone LED circuits up to the wattage limit of the LED circuit driver evenif LED circuits were added to or removed from the output of the LEDcircuit driver.

The higher frequency inverter having a relatively fixed voltage andrelatively fixed frequency output allows for smaller components to beused and provides a known output providing a standard reference HighFrequency LED circuit driver enabling LED circuits to be manufactured involume in existing or reasonably similar LED package sizes withintegrated capacitors or RC networks based on the number of LEDs desiredin the LED circuit package.

Patent publication number 20030122502 entitled Light Emitting Diodedriver (Clauberg and Erhardt) does not disclose the use of a highfrequency inverter driver having a means or keeping a relatively fixedvoltage and relatively frequency in response to changes in the load.According to the present invention described herein, by not havingadditional components such as an inductor or capacitor in series betweenthe LED circuit and the LED circuit driver one LED circuit at a time maybe added to or removed from the LED circuit driver output without havingto change any components, the LED circuit driver or make adjustments tothe LED circuit driver. Additionally, according to this invention thelumen output of the existing LED circuits stays relatively constant dueto the self-regulating nature of each individual LED circuit when drivenwith the relatively fixed frequency and voltage of the LED circuitdriver. This level of scalability, single chip LED circuit packaging andstandardization is not possible with the prior art using an inductor inseries between the LEDs or other components due to the voltage orcurrent increase or drop across the inductors and capacitors in responseto changes in the load.

Prior art for single chip LED circuits, for example those disclosed inO2004023568 and JP2004006582 do not provide a way to reduce the numberof LEDs within the chip below the total forward voltage droprequirements of the source. The present invention however, enables anLED circuit to be made with any number of LEDs within a single chip,package or module by using capacitors or RC networks to reduce thenumber of LEDs needed to as few as one single LED. Improved reliability,integration, product and system scalability and solid state lightingdesign simplicity may be realized with LED circuits and the LED circuitdrivers. Individual LED circuits being the same or different colors,each requiring different forward voltages and currents may be drivenfrom a single source LED circuit driver. Each individual LED circuit canself-regulate current by matching the capacitor or RC network value ofthe LED circuit to the known relatively fixed voltage and frequency ofthe LED circuit driver whether the LED circuit driver is a mains powersource, a high frequency LED circuit driver or other LED circuit drivercapable of providing a relatively fixed voltage and relatively fixedfrequency output.

This again is premised upon the fact that when a real capacitor isconnected in series in one or more lines between an LED and an AC powersource, there is a displacement current through that capacity ofmagnitude: I=2ΠfCV. This means that one can predetermine the amount ofcurrent to be delivered through a capacitance based upon a known voltageand frequency of an AC source.

According to other aspects of the invention, the LED circuit driver maybe coupled to a dimmer switch that regulates voltage or frequency or mayhave integrated circuitry that allows for adjustability of the otherwiserelatively fixed voltage and/or relatively fixed frequency output of theLED circuit driver. The LED circuits get brighter as the voltage and/orfrequency of the LED circuit driver output is increased to the LEDcircuits.

One form of the invention is at least one LED and one diode connectedtogether opposing parallel of each other, two opposing parallel LEDs, anopposing parallel LED string and/or opposing parallel LED matrix havinga capacitor in series of at least one connected junction of theconnected opposing parallel LED configurations within a single chip, asingle package, an assembly or a module. The LED circuit with capacitormay be placed on an insulating substrates such as but not necessarilyceramic or sapphire and/or within various LED package sizes; materialsand designs based of product specifications or assembled on printedcircuit board material. The integrated LED circuit capacitor is of apredetermined value enabling the LED circuit to self-regulate areasonably constant and specific current when coupled to an LED circuitdriver that provides a relatively fixed voltage and frequency output.The LED circuit capacitor may be of a value needed to provide thetypical operating voltage and current of the LED circuit when designedfor coupling to a specific LED circuit driver.

Another form of the invention is an LED circuit comprising at least oneLED and one diode connected together opposing parallel of each other,two opposing parallel LEDs, an opposing parallel LED string and/oropposing parallel LED matrix having a series resistor capacitor (“RC”)network connected together in series or independently in series betweenat least one connected junction of the opposing parallel LEDs and therespective power connection of the LED circuit. The opposing parallelLEDs and RC network may be placed on an insulating substrate such as butnot necessarily ceramic or sapphire and/or within various LED packagesizes; materials and designs based of product specifications orassembled on printed circuit board material. The LED circuit RC networkmay be of a value needed to provide the typical operating voltage andcurrent of the LED circuit when designed for coupling to a specific LEDcircuit driver.

Another form of the invention is an LED circuit comprising a matrix oftwo opposing parallel LEDs connected together in parallel with every twoopposing parallel LEDs having an individual capacitor in series to thepower source connection. The entire parallel array of opposing parallelLED circuits including capacitors may be may be placed on an insulatingsubstrate such as but not necessarily ceramic or sapphire and/or withinvarious LED package sizes; materials and designs based of productspecifications or assembled on printed circuit board material. Theopposing parallel matrix of LED circuits integrated in the LED circuitpackage may be RC network type LED circuits.

Another form of the invention is an LED circuit comprising a matrix ofopposing parallel LEDs connected together in parallel with every set ofopposing parallel LEDs having an individual RC network in series to thepower connection lead.

Another form of the invention is an LED circuit comprising a matrix ofopposing parallel LEDs connected together in parallel, a capacitorconnected in series to at least one side of the line going to the matrixof opposing parallel LEDs with every set of opposing parallel LEDshaving an individual resistor in series to the power connection.

Yet another form of the invention is an LED circuit comprising opposingparallel series strings of LEDs connected together and driven directwith a high frequency AC voltage equal to or less than to total seriesvoltage drop of the opposing parallel series strings of LEDs within theLED circuit.

Another form of the invention comprises a method of driving LED circuitsdirect from an AC power source (“LED circuit driver”) having arelatively fixed voltage and relatively fixed frequency. The LED circuitdriver may be a mains power source, the output of a transformer, agenerator or an inverter driver that provides a relatively fixed voltageand relatively fixed frequency as the load changes and may be a higheror lower frequency than the frequencies of mains power sources. The LEDcircuit driver provides a relatively fixed voltage and relatively fixedfrequency output even when one or more LED circuits are added to orremoved from the output of the LED circuit driver. Higher frequencyinverters with lower output voltages are used as one LED circuit driverin order to reduce component size and simplify manufacturing andstandardization of LED circuits through the availability of higherfrequency LED circuit drivers. The LED circuit driver may also includecircuitry that reduces or eliminates surge current offering a soft-startfeature by using MOSFET transistors, IGBT transistors or otherelectronic means. The LED circuit driver may also be pulsed outputs at ahigher or lower frequency than the primary frequency.

Another form of the invention is a LED lighting system comprising a LEDcircuit array having a plurality of different LED circuits each drawingthe same or different currents and delivering the same or differentlumen outputs that may be the same or different colors and an LEDcircuit driver coupled to the LED circuit array. The LED circuit driverdelivering a relatively fixed t frequency and voltage output allows formixing and matching of LED circuits requiring different forward voltagesand drive currents. The LED circuits may be connected to the output ofan LED circuit driver in parallel one LED circuit at a time within thelimit of the wattage rating of the LED circuit driver with no need tochange or adjust the LED circuit driver as would typically be requiredwith DC drivers and LEDs when increasing or reducing the load with LEDsand other components. Never having to go back to the power source allowsfor more efficient integration and scalability of lighting systemsdesigned with LED circuits. Introducing an inductor and/or an additionalcapacitor such as the impedance circuit described in prior art betweenthe LED circuit drive source and the LED circuits would require changesto the driver or components and prohibit scalability, standardizationand mass production of AC-LEDs with integrated capacitors or RCnetworks.

With the LED circuit driver providing a known relatively constant ACvoltage and frequency, mass production of various LED circuits withspecific capacitor or RC network values would deliver 20 mA, 150 mA or350 mA or any other desired current to the LED circuit based on theoutput of the specified LED circuit driver. The relatively fixed voltageand frequency allows for standardization of LED circuits through thestandardization of LED circuit drivers.

In another aspect, a transistor is coupled to at least one powerconnection of the LED circuit or built into the LED circuit package inseries between the power connection lead and the LED circuit with thetransistor being operable to control (e.g., varying or diverting) theflow of the alternating current through the LED circuit through acapacitance within the transistor.

The foregoing forms as well as other forms, features and advantages ofthe present invention will become further apparent from the followingdetailed description of the presently preferred embodiments, read inconjunction with the accompanying drawings. The detailed description anddrawings are merely illustrative of the present invention rather thanlimiting, the scope of the present invention being defined by theappended claims and equivalents thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a preferred embodiment of theinvention;

FIG. 2 shows a schematic view of a preferred embodiment of theinvention;

FIG. 3 shows a schematic view of a preferred embodiment of theinvention;

FIG. 4 shows a schematic view of a preferred embodiment of theinvention;

FIG. 5 shows a schematic view of a preferred embodiment of theinvention;

FIG. 6 shows a schematic view of a preferred embodiment of theinvention;

FIG. 7 shows a schematic view of a preferred embodiment of theinvention;

FIG. 8 shows a schematic view of a preferred embodiment of theinvention;

FIG. 9 shows a schematic view of a preferred embodiment of theinvention;

FIG. 10 shows a schematic view of a preferred embodiment of theinvention;

FIG. 11 shows a schematic view of a preferred embodiment of theinvention;

FIG. 12 shows a schematic view of a preferred embodiment of theinvention;

FIG. 13 shows a schematic view of a preferred embodiment of theinvention;

FIG. 14 shows a schematic view of a preferred embodiment of theinvention;

FIG. 15 shows a schematic view of a preferred embodiment of theinvention;

FIG. 16 shows a schematic view of a preferred embodiment of theinvention;

FIG. 17 shows a schematic view of a preferred embodiment of theinvention;

FIG. 18 shows a schematic view of a preferred embodiment of theinvention;

FIG. 19 shows a schematic view of a preferred embodiment of theinvention;

FIG. 20 shows a schematic view of a preferred embodiment of theinvention;

FIG. 21 shows a schematic view of a preferred embodiment of theinvention;

FIG. 22 shows a schematic view of a preferred embodiment of theinvention;

FIG. 23 shows a schematic view of a preferred embodiment of theinvention;

FIG. 24 shows a schematic view of a preferred embodiment of theinvention;

FIG. 25 shows a schematic view of a preferred embodiment of theinvention; and,

FIG. 26 shows a schematic view of a preferred embodiment of theinvention;

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 discloses a schematic diagram of a light emitting device 10 foran AC driver according to the invention. The device 10 includes a firstLED 12 connected to a second LED 14 in opposing parallel configuration,a capacitor 16 connected in series between a first junction 18 of thetwo opposing parallel LEDs, a first power connection 20 connected to thetwo opposing parallel LEDs, and a second power connection 22 connectedto a second junction 24 of the two opposing parallel connected LEDs. Adiode may be used in place of LED 12 or LED 14.

FIG. 2 discloses a schematic diagram of a light emitting device 26 foran LED circuit driver according to the invention. The device 26 includesthe device 10 as disclosed in FIG. 1 mounted on an insulating substrate28 such as but not necessarily ceramic or sapphire and integrated intoan LED package 30 that may be various LED package sizes; materials anddesigns based of product specifications or on printed circuit boardmaterial. The device 26 provides power connection leads 32 and may havea first or additional lens 34 that may be made of a plastic, polymer orother material used for light dispersion and the lens may be coated ordoped with a phosphor or nano-particle that would produce a change inthe color or quality of light emitted from the device 10 through thelens 34.

FIG. 3 discloses a schematic diagram of a device 36 having a schematicdiagram of a light emitting device 26 driven directly by an AC driver 38that is connected to the power connections 32 of the device 26 withoutany additional components in series between the AC driver 38 and thedevice 26 such as a capacitor, inductor or resistor. The AC driver 38provides a relatively constant AC voltage and frequency output to thedevice 26 no matter what the total load of the device 26 may be or thenumber of devices 26 changed as long as the load does not exceed thewattage limitation of the AC driver 38. The AC driver 38 may be agenerator, a mains power source, or an inverter capable of providing arelatively fixed voltage and relatively fixed frequency output todifferent size loads. The AC driver may provide a low or high voltageand a low or high frequency to the device 26 according to the inventionas long as the capacitor 16 is the proper value for the desiredoperation of the device 26.

FIG. 4 discloses a schematic diagram of a light emitting device 40 forcoupling to an LED circuit driver according to the invention. The device40 includes a first LED 42 connected to a second LED 44 in opposingparallel configuration. A capacitor 46 is connected in series between afirst junction 48 of the two opposing parallel LEDs and a first powerconnection 50. A resistor 52 is connected in series between a secondjunction 54 of the two opposing parallel LEDs and a second powerconnection 56. A diode may be used in place of LED 42 or LED 44 and theresistor 52 may be put in series on either end of the capacitor 46 as analternate location.

FIG. 5 discloses a schematic diagram of a light emitting device 58 forLED circuit drivers according to the invention. The device 58 includesthe device 40 as disclosed in FIG. 4 integrated into a package asdisclosed in the device 26 in FIG. 2. The device 58 provides powerconnection leads for connecting to an AC driver 38 as disclosed in FIG.3.

FIG. 6 discloses a diagram of a light emitting device 64 for coupling toan LED circuit driver according to the invention. The device 64 includesa first series string of LEDs 66 connected to a second series string ofLEDs 68 in opposing parallel configuration, a capacitor 70 connected inseries between a first junction 72 of the opposing parallel seriesstring of LEDs and a first power connection 74, and a second powerconnection 76 connected to a second junction 78 of the opposing parallelseries string of LEDs. A diode may be used in place of one or more LEDs66 and one or more of LEDs 68 and the LEDs 66 and 68 are integrated intoa package 80 as described in the package 30 disclosed in FIG. 2. alongwith capacitor 70.

FIG. 7 discloses a diagram of a light emitting device 82 for AC driveaccording to the invention. The device 82 includes a first series stringof LEDs 84 connected to a second series string of LEDs 86 in opposingparallel configuration, a capacitor 88 connected in series between afirst junction 90 of the opposing parallel series string of LEDs and afirst power connection 92, and a resistor 94 connected in series betweena second junction 96 of the opposing parallel series string of LEDs anda second power connection 98. A diode may be used in place of one ormore LEDs 84 and one or more of LEDs 86 and the LEDs 84 and 86 areintegrated into a package 100 as described in the package 30 disclosedin FIG. 2 along with capacitor 88 and resistor 94. The resistor 94 maybe put in series on either end of the capacitor 88 as an alternatelocation.

FIG. 8 discloses a diagram of a light emitting device 102 according tothe invention. The device 102 includes a first series string of LEDs 104connected to a second series string of LEDs 106 in opposing parallelconfiguration. A first power connection 108 is connected to a firstjunction 110 of the opposing parallel series string of LEDs and a secondpower connection 112 is connected to a second junction 114 of theopposing parallel series string of LEDs. A diode may be used in place ofone or more LEDs 104 and one or more of LEDs 106 and the LEDs 104 and106 are integrated into a package 118 as described in the package 30disclosed in FIG. 2.

FIG. 9 discloses a circuit diagram of a light emitting device 120according to the invention. The device 120 is similar to the devicedisclosed in FIG. 5 and includes a second series resistor 122 that canbe placed in series on either side of the first capacitor 46.

FIG. 10 discloses a diagram of a light emitting device 124 according tothe invention. The device 124 is similar to the device disclosed in FIG.2 and includes a second series capacitor 126 connected in series betweenthe junction 128 of the opposing parallel LEDs and a power connection130.

FIG. 11 discloses a diagram of a light emitting device 130 according tothe invention. The device 130 has a matrix of individual light emittingdevices 10 as described in FIG. 1 integrated into a package 132 similarto package 30 as described in FIG. 2.

FIG. 12 discloses a diagram of a light emitting device 134 according tothe invention. The device 134 has a matrix of individual light emittingdevices 40 as described in FIG. 4 integrated into a package 136 similarto package 30 as described in FIG. 2.

FIG. 13 discloses a diagram of a light emitting device 138 according tothe invention. The device 138 has a matrix of individual sets of 2opposing parallel light emitting devices 140 with each set having anindividual series resistor to connect to a first power connection 140and a capacitor 146 connected in series between a second powerconnection and the matrix of devices 140. The capacitor 146 mayalternately be in series between the first power connection 144 and allresistors 142. The matrix of devices 140, resistors 142 and capacitor146 are integrated into a package 150 similar to package 30 as describedin FIG. 2.

FIG. 14 discloses a diagram of a light emitting device 152 according tothe invention. The device 152 includes another version of a seriesopposing parallel LED matrix 154 and a capacitor 156 connected in seriesbetween a first junction 158 of the opposing parallel LED matrix 154 anda first power connection, and a second power connection 162 connected toa second junction 164 of the opposing parallel LED matrix. A first powerconnection 108 is connected to a first junction 110 of the opposingparallel series string of LEDs and a second power connection 112 isconnected to a second junction 114 of the opposing parallel seriesstring of LEDs. A diode may be used in place of one or more LEDs 104 andone or more of LEDs 106 and the LEDs 104 and 106 are integrated into apackage 118 as described in the package 30 disclosed in FIG. 2.

FIG. 15 discloses a schematic diagram of a lighting system 168 accordingto the invention. The device 168 includes a plurality of devices 26 asdescribed in FIG. 2 connected to a high frequency inverter AC driveMethod 170 as described in FIG. 3 which in this example provides arelatively constant 12V AC source at a relatively constant frequency of50 Khz to the devices 26. Each or some of the devices 26 may haveintegrated capacitors 172 of equal or different values enabling thedevices 26 to operate at different drive currents 174 from a singlesource AC drive Method.

FIG. 16 discloses a schematic diagram of a lighting system 176 accordingto the invention. The lighting system 176 includes a plurality ofdevices 178, 180 and 182 each able to have operate at different currentsand lumens output while connected directly to the transformer 184 outputof a fixed high frequency AC drive Method 186.

FIG. 17 discloses another schematic view diagram of a light emittingdevice 188 identical to the device 130 disclosed in FIG. 11 andintegrated into a package 30 as described in FIG. 2 for an AC driveMethod according to the invention. The device 188 includes the device130 as disclosed in FIG. 11 mounted on an insulating substrate 28 suchas but not necessarily ceramic or sapphire and integrated into an LEDpackage 30 that may be various LED package sizes; materials and designsbased of product specifications or on printed circuit board material.The device 188 provides power connection leads 190 and 192 and may havea first or additional lens 194 that may be made of a plastic, polymer orother material used for light dispersion and the lens may be coated ordoped with a phosphor or nano-crystals that would produce a change inthe color or quality of light emitted from the device 130 through thelens 194. The device 130 has a matrix of devices 10. The powerconnection opposite the capacitors 16 within the device 130 and part ofeach device 10 is connected to a power connection 196 that is connectedto a solderable heat sinking material 198 and integrated into thepackage 30. The power connection 196 connected to the heat sink 198 maybe of a heavier gauge within the device 130 or 188 than otherconductors. The schematic view of the device 188 provides a side view ofthe package 30 and an overhead view of the device 130 in this FIG. 17.

FIG. 18 discloses another schematic view diagram of a light emittingdevice 198 similar to the device 188 described in FIG. 17 with adifferent light emitting device 200 identical to the device 136disclosed in FIG. 12 and integrated into a package 30 as described inFIG. 2 for an AC drive Method according to the invention. The device 198includes a reflective device integrated into the package 30 foroptimized light dispersion. The light emitting device 200 may be facingdown towards the reflector 202 and opposite direction of light outputfrom the lens 194 if the reflector 202 is integrated into the package 30properly for such a design.

FIG. 19 shows a block diagram of an LED circuit driver 204 having a highfrequency inverter 206 stage that provides a relatively constant voltageand relatively constant frequency output. The high frequency inverter206 stage has an internal dual half bridge driver with an internal orexternal voltage controlled oscillator that can be set to a voltage thatfixes the frequency. A resistor or center tapped series resistor diodenetwork within the high frequency inverter 206 stage feeds back avoltage signal to the set terminal input of the oscillator. An ACregulator 208 senses changes to the load at the output lines 210 and 212of the inverter 206 and feeds back a voltage signal to the inverter 208in response changes in the load which makes adjustments accordingly tomaintain a relatively constant voltage output with the relativelyconstant frequency output.

FIG. 20 shows a schematic diagram of an LED circuit driver 214 having avoltage source stage 216, a fixed/adjustable frequency stage 218, an ACvoltage regulator and measurement stage 220, an AC level responsecontrol stage 222, an AC regulator output control stage 224 and a driveroutput stage 226.

FIG. 21 shows a schematic diagram of the voltage source stage 216described in FIG. 20. The voltage source stage 216 provides universal ACmains inputs 228 that drive a diode bridge 230 used to deliver DC to theLED circuit driver system 214. Direct DC could eliminate the need forthe universal AC input 228. Power factor correction means 232 may beintegrated into the LED circuit driver 216 as part of the circuit. Thevoltage source stage 216 includes a low voltage source circuit 234 thatmay include more than one voltage and polarity.

FIG. 22 shows a schematic diagram of the fixed/adjustable frequencystage 218 as described in FIG. 20. The fixed/adjustable frequency stage218 includes a bridge driver 236 that may include an integrated orexternal voltage controlled oscillator 238. The oscillator 238 has a setinput pin 240 that sets the frequency of the oscillator to a fixedfrequency through the use of a resistor or adjustable resistor 242 toground. The adjustable resistor 242 allows for adjusting the fixedfrequency to a different desired value through manual or digital controlbut keeps the frequency relatively constant based on the voltage at theset terminal 240.

FIG. 23 is a schematic diagram of the AC voltage regulator with voltagemeasurement stage 220 as described in FIG. 20. The AC voltage regulatorwith voltage measurement circuit 220 monitors the voltage at the driveroutput 226 as shown in FIG. 20 and sends a voltage level signal to theAC level response control stage 222 as shown in FIG. 20.

FIG. 24 is a schematic diagram of the AC level response control 228stage. The AC level response control stage 228 receives a voltage levelsignal from the AC voltage regulator with voltage measurement circuit220 as shown in FIG. 23 and drives the AC regulator output control stage224 as shown in FIG. 20.

FIG. 25 is a schematic diagram of the AC regulator output control stage230. The AC regulator output control stage 230 varies the resistancebetween the junction of the drive transistors 232 and the transformerinput pin 234 of the driver output 226 as shown in FIG. 26. The ACregulator output control stage 230 is a circuit or component such as butnot necessarily a transistor, a voltage dependent resistor or a currentdependent resistor circuit having a means of varying its resistance inresponse to the voltage or current delivered to it.

FIG. 26 is a schematic diagram of the driver output stage 226. Thedriver output stage 226 includes drive transistors 232 and thetransformer 236 that delivers an AC voltage output 238 to LED circuitsat a relatively constant voltage and frequency.

1. A lighting system comprising: two or more LED circuits each LEDcircuit having at least two diodes connected to each other in opposingparallel relation, at least one of which such diodes is an LED; at leastone capacitor being connected to and being part of each opposingparallel LED circuit, the capacitor having only one end connected to theopposing parallel LEDs; a driver connected to the one or more LEDcircuits, the driver providing AC voltage and current to the one or moreLED circuits, the driver and the LED circuits forming a driven circuitand the driver and the LED circuits being configured such that LEDcircuits may be added to or subtracted from the driven circuit: (a)without significantly affecting the pre-determined desired output rangeof light from any individual LED; and, (b) without the need to: (i)change the value of any discrete component; or, (ii) to add or subtractany discrete components, of any of the pre-existing driven circuitcomponents which remain after the change.
 2. The lighting system ofclaim 1 further comprising at least one resistor being connected to andbeing part of each opposing parallel LED circuit, the resistor beingconnected in series with the at least one capacitor.
 3. The lightingsystem of claim 1 wherein the AC driver is the mains power and the LEDcircuits are packaged with connectors which accommodate a standardutility outlet.
 4. The lighting system of claim 1 wherein the AC driverprovides high frequency AC voltage.
 5. The lighting system of claim 4wherein the frequency provided by the driver is above 100 cycles persecond.
 6. The lighting system of claim 1 wherein at least one of the atleast two LED circuits has opposing parallel series strings of LEDs. 7.The lighting system of claim 1 wherein the at least two LED circuits arepackaged separately from the driver.
 8. The lighting system of claim 7wherein the packaged LED circuits include one or more lenses.
 9. Thelighting system of claim 1 wherein the capacitors are discretecomponents.
 10. The lighting system of claim 1 wherein a capacitance ofthe capacitors is provided as an inherent attribute of a circuitcomponent which serves to provide a function in addition to or besidesproviding capacitance.
 11. The lighting system of claim 1 including aphosphor coating over the LEDs.
 12. The lighting system of claim 1including lenses for the LEDS and nano-crystals doped in the lenses toaffect the light output of the LEDs.
 13. The lighting system of claim 7wherein the package includes one or more of an integrated heat sinkingmaterial, a reflective material integrated within the package near theLEDs reflecting the light out from the package, and lenses for the LEDs.14. The lighting system of claim 1 wherein the LEDs are organic LEDs.15. The lighting system of claim 5 wherein the driver is an inverter.16. The lighting system of claim 15 wherein the inverter is configuredto provide a relatively constant output frequency and voltage undervariable loads.
 17. An LED device for use with an AC voltage powersource comprising: a first set of two LEDs connected together opposingparallel of each other and forming two connected junctions at opposingends of the two opposing parallel LEDs, a capacitor having a first endconnected to a first connected junction of the two opposing parallelLEDs, a first power connection lead connected to the second end of thecapacitor connected to the first opposing parallel LED junction, asecond power connection lead connected directly to the second connectedjunction of the two opposing parallel LEDs, the entire assembly twoopposing parallel LEDs including capacitor and power connection leadsformed on an insulating substrate material, and; the insulatingsubstrate integrated within a single LED package that provideselectrical connectivity to the LED circuit power connection leads on thesubstrate.
 18. The device of claim 17 comprising more than two LEDsconnected together in two separate series strings opposing parallel ofeach other, a capacitor having a first end connected to a firstconnected junction of the opposing parallel series strings of LEDs, afirst power connection lead connected to the second end of the capacitorconnected to the first connected junction of the opposing parallelseries strings of LEDs, a second power connection lead connecteddirectly to a second connected junction of the opposing parallel seriesstrings of LEDs, the opposing parallel series strings of LEDs includingcapacitor and power connection leads formed on an insulating substrateand integrated within a single LED package that provides electricalconnectivity to the LED circuit power connection leads on the substrate.19. The device of claim 17 comprising more than two sets of two opposingparallel LEDs, each set of two opposing parallel LEDs having anindividual capacitor connected to each set of two opposing parallelLEDs, each individual capacitor having a first end connected to a firstconnected junction of each set of the two opposing parallel LEDs, afirst power connection lead connected to the second end of eachindividual capacitor connected to the opposing parallel LEDs, a secondpower connection lead connected to the second connected junction of eachset of opposing parallel LEDs, each first power connection lead commonlyconnected to a first power connection bus line, each second powerconnection lead commonly connected to a second power connection busline, the opposing parallel sets of LEDs including capacitors and powerconnection leads formed on an insulating substrate and integrated withina single LED package that provides electrical connectivity to the LEDcircuit power connection bus lines on the substrate.
 20. The device ofclaim 17 comprising more than two sets of two opposing parallel LEDs,each set of two opposing parallel LED having an individual resistorconnected to each set of opposing parallel LEDs, each individualresistor having a first end connected to a first connected junction ofthe two opposing parallel LEDs, a first power connection lead connectedto the second end of each individual resistor connected to each set ofthe opposing parallel LEDs, a second power connection lead connected tothe second connected junction of each set of opposing parallel LEDs,each first power connection lead commonly connected to a first powerconnection bus, each second power connection lead commonly connected toa second power connection bus, and; at least one power connection bushaving at least one capacitor connected in series to all the sets ofopposing parallel LEDs, the end of the at least one capacitor oppositethe opposing parallel LEDs having a power connection lead, the sets ofopposing parallel LEDs including the at least one series capacitor andpower connection leads formed on an insulating substrate and integratedwithin a single LED package that provides electrical connectivity to theLED circuit power leads on the substrate.
 21. The device of claim 17having at least one resistor in series of at least one power connectionlead of the opposing parallel LEDs.
 22. The device of claim 17 having asecond capacitor connected to the second connected junction of theopposing parallel LEDs, the second capacitor having a first endconnected to a second connected junction of the opposing parallel LEDs,a first power connection lead connected to the second end of the secondcapacitor connected to the second connected junction of the opposingparallel LEDs.
 23. The device of claim 17 utilizing prepackaged LEDswith lenses.
 24. The device of claim 17 utilizing prepackaged discretecapacitors.
 25. The device of claim 17 having a device with sufficientcapacitance in place of the capacitors.
 26. The device of claim 17having a lens.
 27. The device of claim 17 wherein the LEDs have aphosphor coating.
 28. The device of claim 17 having nano-crystals dopedin a lens to effect the light output of the LEDs.
 29. The device ofclaim 17 having a substrate made of sapphire.
 30. The device of claim 17having a substrate made of gallium nitride.
 31. The device of claim 17having a substrate made of silicon carbide.
 32. The device of claim 17having a substrate made of printed circuit board material.
 33. Thedevice of claim 17 being coupled directly to a fixed high frequencyinverter output having a relatively constant voltage and relativelyconstant frequency AC output.
 34. The device of claim 33 having noseries inductor between the inverter output and the LED circuit device.35. The device of claim 33 having no series capacitor between theinverter output and the LED circuit device.
 36. The device of claim 17further comprising: more than two sets of more than two opposingparallel LEDs, each set of the more than two opposing parallel LEDshaving an individual resistor connected to each set of opposing parallelLEDs, each individual resistor having a first end connected to a firstconnected junction of the two opposing parallel LEDs; a first powerconnection lead connected to the second end of each individual resistorconnected to each set of the opposing parallel LEDs; a second powerconnection lead connected to the second connected junction of each setof opposing parallel LEDs; each first power connection lead commonlyconnected to a first power connection bus; each second power connectionlead commonly connected to a second power connection bus; and, at leastone power connection bus having at least one capacitor connected inseries to all the sets of opposing parallel LEDs, the end of the atleast one capacitor opposite the opposing parallel LEDs having a powerconnection lead, the sets of opposing parallel LEDs including the atleast one series capacitor and power connection leads formed on aninsulating substrate and integrated within a single LED package thatprovides electrical connectivity to the LED circuit power leads on thesubstrate.
 37. The device of claim 36 having at least one capacitorconnected to each set of opposing parallel LEDs.
 38. The device of claim17 comprising more than two sets of more than two opposing parallelLEDs, each set of the more than two opposing parallel LEDs having anindividual resistor connected to each set of opposing parallel LEDs,each individual resistor having a first end connected to a firstconnected junction of the two opposing parallel LEDs, a first powerconnection lead connected to the second end of each individual resistorconnected to each set of the opposing parallel LEDs, a second powerconnection lead connected to the second connected junction of each setof opposing parallel LEDs, each first power connection lead commonlyconnected to a first power connection bus, each second power connectionlead commonly connected to a second power connection bus, and; at leastone power connection bus having at least one capacitor connected inseries to all the sets of opposing parallel LEDs, the end of the atleast one capacitor opposite the opposing parallel LEDs having a powerconnection lead, the sets of opposing parallel LEDs including the atleast one series capacitor and power connection leads formed on aninsulating substrate and integrated within a single LED package thatprovides electrical connectivity to the LED circuit power leads on thesubstrate
 39. The method of claim 37 having at least one capacitor inseries of each set of opposing parallel LEDs.
 40. An LED drivercomprising; one or more capacitors; one or more resistors; two or moreLED circuits each LED circuit having at least two diodes connected toeach other in opposing parallel relation, at least one of which suchdiodes is an LED, the one or more capacitors and the one or moreresistors connected in series between the two or more LED circuits. 41.The one or more capacitors and the one or more resistors of claim abeing integrated into a package providing means of connectivity to anLED circuit and a power source.
 42. A method of operating an LEDlighting system comprising: providing opposing parallel LEDs in acircuit; providing a driver to output high frequency AC current andvoltage to the circuit; adjusting the driver in response to a change inthe load presented by the number of LEDs present or operational at agiven time during operation to provide a relatively constant voltage andfrequency to the circuit.